Systematics of Ancistrocarphus, Diaperia, Evax, Filago, Hesperevax, Logfia, Micropus, Psilocarphus, Stylocline (Asteraceae-Filagininae), Chaenactis (Asteraceae-Chaenactideae); floristics of California-Nevada White Mountains & arid SW North America; rare plants of Nevada & Great Basin.